The FFD for PA chest

The  FFD for PA chest:

• a. 150 cm
• b. 180 cm
• c. 100cm
• d. 180 inches.

The correct answer is b. 180 cm.

The film-to-detector distance (FFD) for a PA chest X-ray is typically 180 cm (71 inches). This distance is important because it affects the size and sharpness of the image. A larger FFD will result in a larger image, but it may also result in a less sharp image. A smaller FFD will result in a smaller image, but it may also result in a sharper image.

The other options are incorrect:

• a. 150 cm is a typical FFD for a lateral chest X-ray, not a PA chest X-ray.
• c. 100 cm is a typical FFD for a skull X-ray, not a PA chest X-ray.
• d. 180 inches is the same as 180 cm, but it is not the standard way to express FFD in radiology.

So the answer is b. 180 cm.